Nodes are often configured in a tree-like network structure, such as a Destination Oriented Directed Acyclic Graph (DODAG) with parent nodes, child nodes, and a root node. In many instances, a node belongs to one DODAG, and one network (e.g., one Personal Area Network (PAN)) at a given moment in time. The nodes often communicate multicast data to each other through the DODAG. For example, a node will forward multicast data destined for members of a multicast group upwards in the network node-by-node to reach a root node. The root node will then distribute the multicast data back down into the network node-by-node to reach the members of the multicast group. This results in a relatively large number of communications, often between nodes that are not members of the multicast group, ultimately causing network congestion. When the nodes are battery-powered, this increases battery consumption.
In addition, in many instances, nodes of separate networks (and separate DODAGs) belong to the same multicast group. Since the nodes are only configured to communicate within their own networks (e.g., intra-PAN communication), this results in members of a multicast group not receiving multicast data.